How to Calculate Materials Needed for Resin Pebble Paving

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Accurately calculating the materials for your resin-bound pebble paving helps you avoid waste, unexpected costs, or project delays. Here’s how to estimate the right amount for your outdoor surface, whether you’re updating a pathway, patio, or driveway.

Essential Calculations: Surface Area and Thickness

First, measure the area you plan to cover in square metres (length × width). Decide on the desired thickness—20mm is standard for most outdoor spaces. Multiply your area by the thickness (in metres) to estimate the volume of aggregate required.

Example: For a 3m × 2m area at 20mm thickness (0.02m), your total volume is 3 × 2 × 0.02 = 0.12m³.
Aggregate density and type can affect the final calculation. Always check your supplier’s guidance.

Determining Resin and Aggregate Quantities

For most resin-bound gravel systems, a 3% resin to aggregate ratio by weight is typical. This means for every 100kg of aggregate, around 3kg of resin binder is needed. As an example calculation, to cover approximately 1.44m² at 20mm thickness, expect to use around 432kg of aggregate and roughly 13kg of resin with a product like the Polirock Polyurethane Binder. Always adjust quantities based on your own mix depth and stone type for best results.

Practical Tips for Ordering and Mixing

Overestimating slightly can cover unexpected surface irregularities or minor miscalculations, but avoid large excess to reduce waste. Check the manufacturer’s instructions for your chosen kit or resin for recommendations on the optimal stone size and compatible resin. Ready-to-use kits such as the Flowstone Complete Permeable Floor Kit can simplify ordering, as they define materials per square metre and include all key components.

When Accurate Material Calculation Matters

Getting your figures right is especially important for larger projects or when using custom-coloured or specialist aggregates. This ensures consistent appearance, structural integrity, and helps keep your project on schedule.

Related guides

How Do You Build Modern Permeable Outdoor Paving

Carefully calculating your resin and aggregate needs ensures a smooth installation of modern, permeable paving and maximises your investment. For further tips on building sustainable outdoor surfaces, visit our main guide on how to build modern permeable outdoor paving.